This study is composed of two parts ; the study on submerged culture of mushroom mycelium by bubble column bioreactors, and the study on separation of protein by reverse micelles.I.Submerged culture of mushroom mycelium by bubble column bioreactors : We devised a novel type of airlift column with a tapered riser which is anticipated to be suitable to the submerged culture of mushroom mycelium. The hydrodynamics (gas holdup and liquid circulation velocity) and the oxygen transfer rate in the airlift column were investigated empirically and theoretically. Conditions to suspend large spherical pellets, which are often formed for the submerged culture of mushroom mycelium, in the standard bubble column were investigated. Next, submerged culture of mushroom mycelium was carried out using two species of mushroom : one is productipn of L-malic acid by Schizophyllum commune, and the other is large-scale culture of Tricholoma matsutake. The optimum conditions of the submerged culture on medium composition, temperature, and air flow rate were found for each mushroom.2. Extraction of protein by reverse micelles : Since mushroom mycelium produces many useful proteins, extraction of protein by reverse micelles was investigated. We found the minimal and optimal AOT concentration for the extraction of lysozyme using reverse micelles. The minimal AOT concentration of a binary protein mixture containing cytocbrome c and lysozyme was found to be smaller than the sum of the minimal AOT concentration of each protein obtained in single protein systems. The addition of low concentration of guanidium salts into the feed solution as a pretreatment decreased the minimal AOT concentration, increased the forward extraction, and enabled the successful recoverry of the protein from the micellar organic phase, while the trehalose addition reduced the forward extraction. Using non-ionic Span 60 reverse micelles, cytochrome c was successfully extracted at concentration higher than the CMC.